Decrpyting a DS rom or ARM7

[Cidthunder]

I am trying to play Shining Force Feathers, but it is only in Japanese. After finding I patch, I patched the game but everytime I try to play it, it tells me I need to find an ARM7 bio(which I did find, don't know how to use it though) or decrypt it(which I don't know how to do). Could I get help with this please?

[SSUPII]

You can find a decrypted version of the game on the internet, like I done with The Sims 3

[Exophase]

The ARM7 BIOS file has to be named nds_bios_arm7.bin and should be in sdcard/DraStic/system